1. Field of the Invention:
The present invention relates to a permanent magnetic material which contains rare earth metals, especially neodymium, and cobalt, to a process for its production and to a use for same.
2. Description of Prior Art:
Material of the above-mentioned type is known, for example, from the article by W. A. A. J. Velge and K. H. J. Buschow in Proc. IEE Conf. on Magn. Mat., pages 45-50, London 1967. According to FIG. 4 of this publication, the (La, Nd)Co.sub.5 alloys mentioned there possess, according to the proportion of neodymium at room temperature, only a slight dependence of the coercitive field strength of .sub.I H.sub.C on the temperature. Such an independence of the coercitive field strenght from termperature variations is very desirable when one uses permanent magnets, for example in electric motors. In addition to this, however, high values of the remanence B.sub.r and of the coercitive field strength .sub.I H.sub.C are also frequently necessary prerequisites which the permaent magnetic material has to fulfill. (La, Nd)Co.sub.5 alloys, however, even at room temperature, where the coercitive field strength is generally greater than at higher temperatures, only reach coercitive field strengths of at most 3kOe. In addition, the coercitive field strength of (La, Nd)Co.sub.5 alloys decreases monotonically as the temperature rises, to an extent dependent upon their composition, even at temperatures which are only slightly above room temperature, so that a use of these alloys as permanent magnets at elevated temperatures, say at 300.degree. C is without interest.